Abstract : CNC machining, as an advanced machining method, is widely used in the processing of high-precision parts with complex surface shapes. This paper introduces the CNC system design for CNC milling of helical cams, consisting of three parts: parameter input, microcontroller control system, and stepper motor drive. Keywords: Helical cam; CNC system; milling machine 1 Introduction Helical cams are commonly used transmission elements in textile machinery. To machine a helical cam, it is necessary to precisely match the rotational displacement and linear displacement of the workpiece along its axis, as well as the tool displacement length, and control the tool running direction and workpiece rotational displacement to obtain the required shape and size, meeting the accuracy requirements. Due to the complex surface shape, the accuracy of traditional machining methods is difficult to guarantee, and the productivity is low. Especially for some easily damaged cam elements in imported textile machinery, the accuracy is difficult to guarantee, often requiring reliance on foreign monopolized technology. Therefore, the author carried out CNC modification of a conventional milling machine. The modified machine tool allows the stepper motor to change speed arbitrarily and can arbitrarily change its running direction and displacement length during the machining process, thus producing qualified helical cam elements. For machining cam elements with different base circle diameters, only the gear transmission between the corresponding motor output shaft and the indexing head input worm gear needs to be changed to obtain the appropriate transmission ratio. After the modification, the machine tool achieves automated machining for all processes except vertical feed, tool changing, and workpiece loading and unloading, improving machining accuracy and production efficiency. Error analysis shows that if the pulse equivalent is taken as 0.01mm, this system can reduce the actual transmission error caused by a single cam rotation to less than ±0.005mm, i.e., one pulse equivalent, and also reduce the cumulative error to less than one pulse equivalent. [b][align=center]For details, please click: Design of CNC System for Helical Cam Milling[/align][/b]